Core Data and NSPredicate for a to-many relationship

I have a Core Data model in which a Task entity includes an optional to-many relationship excludedOccurrences. One of the properties of excludedOccurrences is start, which is an NSDate object. The ExcludedOccurrence entity has an inverse mandatory to-one relationship to the Task entity.

In order to fetch the tasks for a specified day, I need to make sure that the specified day does not appear as the start property of any ExcludedOccurrence entity. One of the sub-predicates I am trying to use is therefore